This invention relates to piperazine derivatives of theophylline; to their utility as treatment compounds for respiratory and allergic diseases, and to their properties as vasodilators.
Theophylline, itself, is well known as a diuretic, cardiac stimulant and smooth muscle relaxant. Addition of the piperazine containing substituent confers a range of pharmacologic activities which render the resulting compounds useful in the symptomatic treatment of asthma, hay fever and other respiratory diseases such as, for example, the common cold. Those compounds of others most similar in structure to the compounds of the present invention are those in European patent application No. 23,350. Also, similar compounds have been described by us in U.S. application Ser. No. 224,710, filed Jan. 12, 1981, U.S. Pat. No. 4,374,835. The compounds of the present invention are also vasodilators.